Control for hydraulic mechanism



Nov. 3, 1942. f w. P. KELLETT JR 2,301,122

CONTROL FOR HYDRAULIC MECHANISM Filed July 15, 1940 5 Sheets-Sheet l o O O o Nov. 3, 1942. I w. P. KELLETT, J R 2,301,122

CONTROL FOR HYDRAULIC MECHANISM Filed July 15, 1940 3 Sheets-Sheet 2 A l 5 n o 39 38 41 fig TS C3 as 1 1 T B i i J r J a M J a Patented Nov. 3, 1942 CONTROL FOR HYDRAULIC MECHANISM William P. Kellett, Jr., New York, N. Y., assigno to William P. Kellett, New York, N. Y.

Application July 15, 1940, Serial No. 345,578

TClaims- (Cl. 103-41) The principal objects of the invention are to provide means for controlling the operation of the hydraulic meansfor raising and lowering the deck of transport vehicles which will enable a very flexible manipulation of the deck in permitting the operation of the ends of the deck either separately or in unison.

The principal feature of the invention consists in the novel construction and arrangement of dual pressure pumps and dual control valves in a hydraulic lift mechanism for raising and lowering a vehicle deck whereby one pump and valve is associated with a forward pair of hydraulic lifts and the other pump and valve is aszcciatod with the rear pair of lifts.

In the accompanying drawings,

Figure 1 is a diagrammatic perspective view of a group installation of hydraulic lifts for a movable deck showing the forward and rearward pairs of lifts coupled with the improved valve control.

' Figure 2 is a longitudinal sectional detail of one of the hydraulic lifts.

Figure 3 is an enlarged plan view of the control valve casing.

Figure 4 isa side elevational view of the control valve casing.

Figure 5 is a small perspective view. of control valve and operating levers.

Figure 6 is a vertical sectional view through the valve casingshowing one of the valves, taken on the line 6-6 of Figure 4.

Figure 'l is an elevational view of one of the pumps with the cover removed.

Figure 8 is a longitudinal mid-sectional view the through the valve casing showing the position of w the control valves and the relation of the ports when both valves are directing the fluid to both forward and rear lifts to raise the lifts.

Figure 9 is a view similar to Figure 8 showing the position of the valves and port when both sets of lifts are being held in a stationary position.

Figure 10 is a view similar to Figure 8 showing the position of the valves and ports when both sets of lifts are being lowered.

Referring to the accompanying drawings the hydraulic lifts, as shown in Figure 2 are of a well known type comprising a cylinder I having inlet and exhaust openings 2 and at the bottom and top thereof. A piston 4 operates within each cylinder and operates a ram 5 which extends through the top and is connected with the deck to be operated. Each cylinder is formed with a by-pass 6 adjacent to the top to limit the upward movement of the piston by allowing the motive fluid to circulate around the piston when it rises to uncover the lower end of the by-pass.

In the assembly of lifts shown in Figure l as supporting the deck X of a vehicle, the front pair of lifts A and B are connected by. a pipe 1 leading from the top or discharge port of A to the bottom or inlet port of B. The inlet port of A is connected by pipe 8 to the discharge port 9 at one end of the valve casing 10.

The lift C of the rear pair has its bottom inlet port connected by pipe II to the discharge port I2 of the valve casing l0 arranged at the end opposite to the port 9 and the discharge of 1m C is connected by pipe l3 to the inlet of the other rear lift D.

The discharge ports of lifts B and D are connected by pipes I4 and I6 respectively to an oil reservoir l6. The reservoir I6 is connected by pipe H to a central inlet port i8 in the valve casing l0.

The valve casing I9 is formed with a central chamber l9 which is connected by a vertical passage to a longitudinal passage 2| which extends to either end of the casing where it opens into the central region 22 of the gear pumps 23 which are-arranged at each end of the casing.

The shafts 24 and 25 operating the gear pumps extend through horizontal orifices in the casing l0 and either one may be driven at its outer end by suitable means.

A cap 26 is arranged to cover the end of the pump shaft not connected directly to the motive power.

The fluid which is drawn into and through the pumps from the passage 2i is discharged into passages 21 and 28 which are arranged adjacent to.the discharge passages 9 and I2 respectively.

A pair of cylindrical valve sleeves 29 are inserted into parallel orifices extending through the valve casing l0 and each of these sleeves is formed with oppositely disposed ports 30 and 3| arranged at the top and bottom respectively, the

top ports communicating with the pump discharge ports 21 and 28 while the bottom ports communicate with the chamber l9 within the valve casing. Each valve sleeve i provided with a port 32 communicating respectively with the discharge ports 9 and I2 in the valve casing leading to the lifts A and C respectively.

A port 33 is arranged in each valve sleeve in a position about from the port 30 and directly opposite the closed area between the ports 3| and 32. The port 33 of each sleeve opens into the chamber I9 of the valve casing Ill.

The valve sleeves are secured in position by plugs 34 threaded into the valve casing at each end of the sleeve and these plugs are fitted with suitable packing nuts 35.

The valve sleeves 29 are each formed with a tapered bore and housed therein are the tapered valves 26 which have spindle ends 31 and 36 extending through the packing nuts.

A coiled compression spring 39 encircles the spindle end 31 and its pressure is regulated by adjusting nuts 40 threaded on the end of the spindle. An operating lever 4| is secured on the opposite spindle end 38.

The valves are preferably arranged with their tapers in opposing directions so that an operating lever may be on either side of the valve casing to permit the attachment of operating rods and levers 42 as shown in Figure 5.

Each valve 36 is cut awayin a region centrally between its ends leaving a diametrically disposed blade portion 42' which has its outer ends of sufflcient width to cover the ports 30, 3| and 32 or 33 as may be required in operation.

The end portions are also cut away to reduce frictional surfaces and it is found desirable to connect the central recesses in the valve with the outer'recesses by suitable drill holes 43 to equalize pressures and to lubricate the valve surfaces.

On reference to Figure 8 it will be seen that with the valves positioned as shown the ports 33 are closed and the ports 30 and 32 are connected so that the fluid discharged from the pumps will flow to the cylinders A and C through the ports 9 and I2 respectively and operate both sets of lifts in unison.

If desired either one or the other sets A and B or C and D may be operated by manipulating the valves.

When the valves are turned to the position shown in Figure 9, the ports 9 and H are closed and the lifts will be held from raising or lowering and the fluid from the pumps will by-pass through ports 30 and 33 back to the chamber I9.

When the valves are turned to the position shown in Figure 10, the fluid from the pumps will by-pass through the ports 30 and 33 but the ports 32 are connected with ports 3| so that the fluid from the lifts will flow freely back to the reservoir IS by way of port It! and pipe IT and allow the pistons to lower in the lift cylinders. The lowering of the load may be regulated effectively by manipulating the valves to open or close the valve ports to any desired degree.

It will be appreciated that with an arrangement of valves and circulating pipes to and from the lifts such as described it will be possible to raise or lower either end of a car or truck deck independently or the whole deck may be raised or lowered at any desired speed within the scope of the pumps and the load and a very accurate control is possible so that loading or unloading of the vehicle may be accomplished under the most desirable conditions.

It will be further evident that a control mechanism such as described eliminates the necessity of providing costly and troublesome reverse drive mechanisms or selective control drive forv the pumping mechanism so that only a simple form of drive connection with a suitable source of power is required.

What I claim as my invention is:

1. In a mechanism of the class described, a pair of rotary fluid pumps, a common casing supporting said fluid pumps, a common drive means for said pumps rotatably supported in said casing, said casing having interiorly thereof a separate valve chamber associated with each pump having inlet and discharge ports within said casing connected with the intake and discharge sides of the respective pump, and valves in said chambers operable independently or in unison, whereby a compact dual pumping and control assembly is provided.

2. Mechanism as claimed in claim 1 in which said valve chambers are oppositely tapered in side-by-side relation and the valves are of the tapered type and provided with operating spindles projecting respectively at opposite sides of said common casing.

33. Mechanism as claimed in claim 1 in which ported sleeve members are fitted into said casing forming said respective valve chambers, said sleeves being clamped between plug members threaded into the casing at the ends of the sleeves.

4. Mechanism as claimed in claim 1 in which said valve chambers are oppositely tapered in side-by-side relation and the valves are of the tapered type, said valves each having spindles projecting at opposite sides of the casing, means co-operating with said spindles at opposite sides of the casing for resiliently urging said valves into sealing relation to the sleeves, means for sealing all of said spindles, operating arms secured to certain of said spindles, and means for rocking said operating arms either individually or in unison.

5. In mechanism of the class described, a plurality of pumps of the inter-meshing gear type mounted in axially spaced relation at opposite ends of a control valve casing, individually operable valves arranged in said casing, the respective gears of the two pumps being connected by shafts extending through the casing either one of which is adapted to'form the drive shaft, said valves being of the rotatable type and extending through the casing in substantial right angular relation to the axes of the pump shafts.

6. In 8. raising and lowering mechanism of the hydraulic type, a valve casing having a central fluid chamber adapted for connection to a supply reservoir, a pair of rotary fluid pumps mounted on said casing in axially spaced relation at opposite sides of said central fluid chamber and each having a fluid intake connected to said central fluid chamber, renewable valve sleeves removably fitted in said casing between the respective pair of rotary pumps, ports in each of said valve sleeves connecting said central fluid chamber with the interior of said sleeves at peripherally spaced points, ports in said sleeves connected with the discharge sides of said pumps, pressure outlet ports in said sleeves adapted for connection with pressure-responsive means, and rotary control valves in said sleeves co-operating with said series of ports and adapted to be individually or collectively operated.

'7. Mechanism as claimed in claim 6 in which each sleeve is cylindrically surfaced and fitted in cylindrically surfaced sockets formed in said valve casing and having their adjacent sides exposed within said central fluid chamber and provided with two ports leading to the said cen-- tral fluid chamber at circumferentiaily spaced points, one of which two ports is disposed substantially diametrically opposite the pump discharge receiving port the port for connection VVILLIAl/i P. KELLETT, JR. 

